This invention relates to an apparatus for reducing siltation in cul-de-sac type ship berths.
In the past, there have been attempts to develop a suitable device for reducing the flow of sediment (silt) into ship berths, however all have been unsuccessful. In 1980, Scripps Institute of Oceanography constructed and installed a device but it was soon removed because it required difficult and lengthy procedures to open and close. In 1981, Scripps deployed a second device but it too was unsuccessful and was removed four months after installation.
Two other attempts were made in the Netherlands, one in 1982 and one in 1987. Both of these devices had no moving parts and were supposed to allow ships to drive right over the top--both were unsuccessful and were soon damaged by contact with ship bottoms.
Other devices, such as dams and oil containing devices have been developed to both float and remain below the sea surface. All utilize some sort of barrier or containment means with floatation elements that may be inflated/deflated to raise/lower the device into position.
Representative patents showing various devices include U.S. Pat. No. 4,252,461; U.S. Pat. No. 3,922,861; U.S. Pat. No. 3,859,796; U.S. Pat. No. 3,839,870; U.S. Pat. No. 3,783,622; U.S. Pat. No. 3,710,577; U.S. Pat. No. 3,708,983; and U.S. Pat. No. 4,280,438.
However, none of these devices provide an apparatus that may be quickly and easily, raised, or lowered; that may be easily removed; that will prevent sedimentation in a ship berth; that ma be vertically positioned anywhere below the sea surface; that may be lowered by direct means; and that will fold in a repeatable manner when lowered.
Thus, there is a need in the art for providing an apparatus for reducing siltation in cul-de-sac type ship berths yet is easily and quickly lowered and raised to allow deep draft ships to enter/exit the berth, is easily removed for repair, maintenance or dredging and permits shallow draft boats to enter/exit the berth without lowering.
It is therefore an object of the present invention to reduce sedimentation in ship berths especially cul-de-sac type berths. It is another object of the present invention to provide a device that is easily and quickly raised or lowered. It is a further object of the present invention to provide a device that may be quickly and easily removed for repair or maintenance or when dredging of the berth is required. It is yet another object of the present invention to provide an apparatus that, when installed and operating in the fully extended or "up" position, will allow ships with shallow drafts, for example, harbor, maintenance or personnel craft to enter or leave a berth without impairment by the present invention. It is another object of the present invention to provide an apparatus that may be lowered by direct means. It is a further object of the present invention to provide an apparatus that when lowered will fold in a repeatable and predictable manner. It is yet another object of the present invention to provide an apparatus that may be vertically positioned anywhere above the ocean (sea) bottom.